LINQ TO XML求解

Question

<?xml version="1.0" encoding="utf-8"?>
<Products>
  <Item>
    <ID>4</ID>
    <GoodID>1552</GoodID>
    <Price>3.85</Price>
    <ZK>0.35</ZK>
    <Quantity>1</Quantity>
  </Item>
  <Item>
    <ID>5</ID>
    <GoodID>1552</GoodID>
    <Price>3.19</Price>
    <ZK>0.29</ZK>
    <Quantity>12</Quantity>
  </Item>
  <Item>
    <ID>6</ID>
    <GoodID>1552</GoodID>
    <Price>3.19</Price>
    <ZK>0.20</ZK>
    <Quantity>34</Quantity>
  </Item>
</Products>用LINQ　TO　XML　方式从中获取ID　及数量　存在的　ZK
比如：ID＝1552且　数量＝12　返回折扣　0.29　
要求是：ID＝1552　且数量＝13　返回　0.29　但是　数量＝34　返回0.20

Answer 1

void Main()
{
  string xml = @"<?xml version=""1.0"" encoding=""utf-8""?>
<Products>
<Item>
<ID>4</ID>
<GoodID>1552</GoodID>
<Price>3.85</Price>
<ZK>0.35</ZK>
<Quantity>1</Quantity>
</Item>
<Item>
<ID>5</ID>
<GoodID>1552</GoodID>
<Price>3.19</Price>
<ZK>0.29</ZK>
<Quantity>12</Quantity>
</Item>
<Item>
<ID>6</ID>
<GoodID>1552</GoodID>
<Price>3.19</Price>
<ZK>0.20</ZK>
<Quantity>34</Quantity>
</Item>
</Products>";
XElement xmlPage = XElement.Parse(xml);
 
var query = from x in xmlPage.Descendants("Item")
select new
{
ID=x.Element("GoodID").Value,
Quantity=x.Element("Quantity").Value,
ZK=x.Element("ZK").Value
};

query.ToList().ForEach(q=>Console.WriteLine("ID="+q.ID+"   Quantity=" +q.Quantity+"   ZK="+q.ZK));
/*
ID=1552   Quantity=1   ZK=0.35
ID=1552   Quantity=12   ZK=0.29
ID=1552   Quantity=34   ZK=0.20 */
}

Answer 2

 var query = xmlPage.Descendants("Item").Select(x => new
                        {
                            ID = x.Element("ID").Value,
                            GoodID = x.Element("GoodID").Value,
                            Quantity = x.Element("Quantity").Value,
                            ZK = x.Element("ZK").Value
                        });

Answer 3

void Main()
{
Console.WriteLine(GetZK(1552,12));  //0.29
Console.WriteLine(GetZK(1552,34));  //0.20
}
string GetZK(int id,int Quantity)
{ 
 string xml = @"<?xml version=""1.0"" encoding=""utf-8""?>
<Products>
<Item>
<ID>4</ID>
<GoodID>1552</GoodID>
<Price>3.85</Price>
<ZK>0.35</ZK>
<Quantity>1</Quantity>
</Item>
<Item>
<ID>5</ID>
<GoodID>1552</GoodID>
<Price>3.19</Price>
<ZK>0.29</ZK>
<Quantity>12</Quantity>
</Item>
<Item>
<ID>6</ID>
<GoodID>1552</GoodID>
<Price>3.19</Price>
<ZK>0.20</ZK>
<Quantity>34</Quantity>
</Item>
</Products>";
XElement xmlPage = XElement.Parse(xml);
 
var query = (from x in xmlPage.Descendants("Item")
            where x.Element("GoodID").Value.Equals(id.ToString()) 
     && x.Element("Quantity").Value.Equals(Quantity.ToString())
      select  x.Element("ZK").Value).FirstOrDefault();
return query==null?"":query;
}

Answer 4

XElement xel= XElement.Parse("");
var query = from x in xel.Descendants("Item")
where (string)x.Element("GoodID").Value.Equals(id) 
&& x.Element("Quantity").Value.Equals(Quantity)
select x.Element("ZK").Value;